In clinical practice, trephines are often used to cut out a cancellous bone for transplantation or a pathological specimen. However, the trephines usually fail to extract a core, or break the core into several sections because it is unable to transect a core base during extraction. Even a trephine with shallow threads on its inner wall is unable to obtain an intact core, thereby affecting the quality of the obtained core. In addition, intact cores are generally required in the applications such as manufacture, life and exploration; however, a traditional trephine can only cut off the core periphery instead of the core base.